Chatter under hard acceleration

[Agent]

My bike is making me nervous. I've got 21,000 miles on her and she started making a noise yesterday.

When I accelerate hard from a dead stop, I get a chatter and a high-pitched screech from what I assume is the clutch. The closest thing I can relate it to is when you engage the blade on a belt-driven riding lawnmower.

It still shifts fine, rides fine, and will pull away from a stoplight at a normal pace with no problem. The bike did sit for about a month while I scraped together the money for a new tire.

Does anyone else have this issue or know what it could be? If I haven't given enough information, feel free to ask and I'll try my best to answer.

Thanks.

 

[670cc]

Was this new tire just recently installed? Possibly the problem is a result of that work having been done. If it was the rear tire, is the chain way too tight?

 

[Agent]

Good question, Greg. I just went out and checked and the chain is actually pretty loose. It's loose enough to need some attention when I get home. Do you think that the extra slack (about 2 1/4 inches total) would cause the noise?

 

[Deleted member 1183]

I can't see a loose chain making such a noise. My thinking would be glazed clutch plates screeching under heavy use. Are you using full synthetic oil ?

 

[StratTuner]

I can't see a loose chain making such a noise. My thinking would be glazed clutch plates screeching under heavy use. Are you using full synthetic oil ?

What would be the worst oil to use for the NC's "wet" clutch?

 

[Agent]

I use Honda GN4 oil, whatever the standard weight it says to use in the manual. I can't remember what it is right now.

I would hope the clutches aren't glazed. I don't ride it hard often and my mileage is probably 90% highway-10% town. I guess anything is possible though. Is there a way that I could fix them or would they have to be replaced? I know that I had to soak the new clutches in oil before I replaced the ones in my Yamaha. Could the NC clutches have dried out in the time the bike was parked?

I'm really bad at troubleshooting, so any suggestions help.

 

[ld_rider]

I'm really bad at troubleshooting, so any suggestions help.

Why not have the dealer/independent shop look at it and tell you what is wrong?
Have you checked your brake pads/rotors?

 

[bamamate]

Have you replaced the chain from the factory one?
When my factory chain was toast it got real noisy.

 

[Agent]

I have not changed my brakes. I'm afraid that it won't reproduce the noise if I take it in. I'm not too keen on handing a mechanic my keys and saying, "ride it hard." If it continues or gets worse, I may have no choice.

Yes to the chain. I put a new DID X ring on around 4,000 miles ago. Maybe it's just the chain causing issues. When I checked, the adjusting nuts had loosened and backed themselves almost off the bolt. I snugged them up, but I'll have to put it all back in order when I get home and have my tools. We'll see if that helps.

 

[MZ5]

The high-pitched screech noise may be from the air intake system. My bike makes a high pitched noise at wide-open-throttle that one might describe as either a screech or perhaps a whistle. It has done it since new, and changing air filters and checking the air box for good seal does not make it go away. If your bike stops making that sound when you close the throttle a bit from wide open, I bet it's the same thing.

Note here that I haven't positively identified the cause of the noise. So, it _could_ be something to do with the air box or boot connecting it to the intake manifold. I _have_ done a little testing for leaks and haven't found any. I've chosen to assume it's something to do with the shape(s) of the airbox that makes it make this noise

 

[TigerDude]

bikes sit for a month at a time all the time. That isn't it.

 

[ld_rider]

I'm afraid that it won't reproduce the noise if I take it in. I'm not too keen on handing a mechanic my keys and saying, "ride it hard."

Don't let the fear of a mechanic "riding it hard" or a failure to reproduce the noise scare you. I would instead be scared of a bunch of internet dudes trying to troubleshoot a mechanical problem with potentially <fatal> consequences.

I would have an actual motorcycle mechanic look it over if I were really worried...

But that is just me ;-)

 

[Deleted member 1183]

What would be the worst oil to use for the NC's "wet" clutch?

I don't understand the question, but I used a semi synthetic 10/40 in mine. My thinking is that gentle riding together with a very high quality oil could possibly result in clutch plate glazing ?

 

[TigerDude]

Since the tire was changed, it seems to me that either the chain or the wheel alignment would be the 1st things to look at.

 

[Agent]

I finally got time to adjust the chain. Didn't get time to ride, but I did take over an inch of play out of the chain. It looks like it'll be a few days before I can ride again. We'll see how it does then.

@MZ5, that's an interesting possibility. I don't know how I would test for that. If tightening the chain doesn't fix it, I'll look into other possibilities.


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